1. Field of the Invention
This invention relates in general to portable electronic devices and more particularly to methods for wirelessly charging such devices.
2. Description of the Related Art
In today's marketplace, there is a plethora of portable electronic devices, many of which are powered by rechargeable batteries. Some manufacturers have begun producing chargers that can wirelessly charge these batteries. In such an arrangement, the charger can include a primary coil, and the rechargeable battery can include a secondary coil. When a time-varying current is applied to the first coil in the charger, a charging current can be generated in the secondary coil. Wireless charging is convenient in that it is unnecessary to couple any wires to the portable electronic device that houses the battery.
Many of the devices that are capable of being wirelessly charged, however, also have receptacles for receiving a charging wire from a conventional charger. In addition, the portable electronic device currently has no way to monitor the charging current from a wireless charger. Thus, the possibility exists that an end user will couple a standard charger to the portable device as it is being wirelessly charged, which may double the charging current. Consequently, the charging indicator, which informs the user of the amount of charge on the battery, may be inaccurate, and even worse, this excess current may damage the components of the portable device.
Even if the user avoids this scenario, the charging indicator may still provide erroneous readings. This disadvantage exists because many portable electronic devices rely on current thresholds to produce the readings of the charging indicator, particularly when the battery reaches its maximum charge voltage but is not yet fully charged. As noted earlier, there is no current way for the portable electronic device to monitor the charging current from a wireless charger.